(19)
(11) EP 0 696 132 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.01.1997 Bulletin 1997/01

(43) Date of publication A2:
07.02.1996 Bulletin 1996/06

(21) Application number: 95305327.9

(22) Date of filing: 31.07.1995
(51) International Patent Classification (IPC)6: H04N 1/405
(84) Designated Contracting States:
DE FR GB

(30) Priority: 03.08.1994 US 285326

(71) Applicant: XEROX CORPORATION
Rochester New York 14644 (US)

(72) Inventors:
  • Metcalfe, David J.
    Marion, NY 14505 (US)
  • Shiau, Jeng-Nan
    Webster, NY 14580 (US)
  • Williams, Leon C.
    Walworth, NY 14568 (US)

(74) Representative: Reynolds, Julian David et al
Rank Xerox Ltd Patent Department Parkway
Marlow Buckinghamshire SL7 1YL
Marlow Buckinghamshire SL7 1YL (GB)

   


(54) A method of high addressability error diffusion


(57) A method and system implements a high addressability characteristic into an error diffusion process. A grey level value representing a pixel is received. The grey level value has a first resolution which corresponds to an original input resolution. The grey level value is interpolated (S30) to generate subpixel grey level values which correspond to a second resolution. The second resolution is higher than the first resolution and corresponds to the high addressability characteristic. A threshold circuit thresholds the interpolated grey level value and generates (s180) an error value as a result of the threshold. The error value has a resolution corresponding to the first resolution. A portion of the error value is diffused (S190) to adjacent pixels on a next scanline.






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